This invention relates to single-lens reflex cameras, and more particularly to an interlocking device for an indication device in the finder of a single-lens reflex camera.
In a single-lens reflex camera whose pentaprism is replaceable, the coupling mechanism for controlling the exposure-meter indication mechanism, the exposure data (lens stop values, shutter speeds, etc.) displaying mechanism, etc. are included in the pentaprism housing or in the camera body. In a camera with the coupling mechanism provided in the pentaprism housing, the latter is, in general, necessarily large because of its pentaprism function and also the configuration of the coupling mechanism which it must contain. Thus, such an arrangement is not preferable from the point of view of operability, weight, balance and design. On the other hand, in a camera in which the coupling mechanism is provided in the camera body, data must be optically transmitted into the finder's optical system because positioning the indication mechanism within the optical system would unacceptably interfere with the assembly and/or removal of the mirror box. Therefore, the dimension, brightness and visibility of the indication data are often insufficient. Accordingly, in the camera with a replaceable pentaprism, it is desirable that the data indicator be of the direct-viewing type by providing it in the field of vision in the vicinity of the focal plate. However, since this direct-viewing type indicator is integral with the finder's optical system, that is, is mounted on the mirror box, the coupling section to the operation section provided on the camera body will need adjustment during an assembling process or a disassembling process for repair, which leads to a reduction in production.